The filter is divided into XH-5 (R12 series) XH-7 (134A) XH-9 (R600A series). One thing to keep in mind is that only high-labeled alternatives to low-labeled. The low-grade absolute can not replace the high-level filter. Their difference is mainly on the desiccant and molecular sieve. The higher the number, the higher the corresponding technical specification. This is also designed by the characteristics of the refrigerant. Please pay attention to it so as to avoid the poor cooling of the equipment after repair. Its main function is to filter water and impurities in the system to ensure that the refrigeration equipment is operating properly. However, it does not filter the traces of water or impurities that enter the system due to maintenance. Please pay attention to this point, in the maintenance of the site can not have water, so as not to cause the system ice blocking.